Herpes simplex virus (HSV) is a large DNA virus which induces the synthesis of many proteins in the infected cell. The objective of this project is to characterize the function of some of these proteins. The approach used will build on preliminary experiments in which specific virus-induced proteins have been purified from infected cells by conventional chromatographic methods and by affinity chromatography on DNA-cellulose columns. Proteins selected by their ability to interact with DNA will be purified and each purified protein will be tested for DNA-binding characteristics, for enzyme function, and for their interaction with known enzymes. This biochemical approach will be combined with the use of specific antisera to each purified protein and the study of ts mutants to characterize further protein function. Preliminary work along these lines has identified both the structural gene for HSV DNA polymerase and the virus-induced protein with this activity. Such studies will also enable a search for specific virus-induced proteins in transformed cells. Preliminary studies already indicate the presence of specific DNA-binding proteins in certain types of HSV transformed cell lines.